Seven bidders for superfast mobile broadband in Britain were announced Thursday but the boost to U.K. government coffers remains speculative ahead of the auction next month. That said, the Treasury is hoping to pocket at least £3.5 billion.

Telecoms regulator Ofcom will accept bids for 4G spectrum [these being the electromagnetic frequencies that allow data to be transmitted wirelessly] from late January, but its mandate of maximising consumer benefit is at odds with the cash-strapped U.K. government’s hoped-for windfall expectations.

Reuters

An upgrade to 4G will allow mobile, tablet and laptop users to download data at least five times faster than currently possible on 3G networks, with a hopefully commensurate increase in business activity, providing a much-needed economic boost.

Despite a reserve price of just £1.3 billion, Chancellor George Osborne revealed in his half-yearly budget statement earlier this month that the Office for Budget Responsibility forecast assumed the government would raise £3.5 billion from the auction of its 4G mobile-spectrum, which would go some way to offsetting lower-than-expected tax receipts.

This looked ambitious until last week when the Netherlands raised double its estimates in its own 4G spectrum auction.

However Ofcom chief executive Ed Richards Thursday cautioned about reading too much into the amounts raised in other 4G auctions across Europe…